Froth flotation of iron-bearing minerals from feldspathic ores



Patented Mar. 31, 1953 UNITED STATES PATENT OFFICE FRZQTH FLOTATIONOFIRONeBEARING MIN- ERALS FROM FELDSPATHIC ORES Mason "K. Banks,Asheville, N. 0., assignor to Tennessee Valley Authority, acorporationof the United. States 9 Claims.

The inventionherein described maybe manufactured and usedby or for the.Governmentior governmentalpurposes without payment to me of i anyroyalty thereon.

This invention relates to the beneficiation of feldspathic ores. ."Inconcerns particularly the .removaI-of iron-bearing mineralsfrom suchores by froth flotation.

Feldsparforusein the glass trade must contain not .more than 0.1 percent iron, as F6203, not more than 69 per cent silica, and. not lessthan 18.0 per-cent alumina. Sizespecifications require that the feldsparcontainnot more than3 per cent of plus20-.mesh.material and not morethan per cent of minus 200+mesh material.

.Feldspar. for use in the ceramic trade is ground to pass a 200-meshscreen. The alumina content usually should not be less than 18 per cent,although a few manufacturers place this requirement as low as 1.7 percent. The principal requirement as to iron content is removal of allparticles which mightcausespotting or discoloring of fired ware. Thereis.no definite specification oniron content except that spottingor-discoloring dueto iron must notoccur-when ceramic ware is fired.However, thereis usually a close relationship between.spottingand ironcontent of feldspar recovered as a flotation concentrate. Iron,expressed.as F6203, usually must be less than 0.05 per cent if spottingis to be avoided, and often should be around-.0-.03 per cent.

.It is a general practice to recover feldspar from feldspathic ores as aflotation concentrate at minus 20 mesh. If produced for theglassmarket,the concentrate is then dried and shipped. If producedfor the ceramicmarket, the concentrate is dried, is sometimes blended with block spar,ground to'minus ZOOmesh, sized, and shipped.

Large deposits of alaskite, a feldspathic .ore, existin western NorthCarolina. This material is apegmatitic-granite, varying in texture fromthe coarseness oipegmatiteto'the fineness of granite. It is ratheruniform in composition, comprising oligoclase. quartz, microcline,andmuscovite, with small amounts of garnet and biotite present,especially near the contacts.

Oligoclase is a soda-lime feldspar, and microcline is-a potash feldspar.Muscovite and biotite aremicaceous minerals. Biotite contains iron inits molecule. Muscovite, while it contains no iron sec. 266) in itsmolecule,.isfrequentlystained red or black by thin films of. iron oxidebetweenthe laminae. Iron-containing garnets probably are present asalmandite (3FeO:Al2Os 2SiOz) and/ or .andradite (BCaO-FezOs 3SiO2) Analaskite ore sample, typical .of thatnow being used in the production offeldsparin western North Carolina, had the following chemicalan- U. S.Patent No. 2,483,192 discloses a process for decreasingtheferrous-metals silicates content of feldspathicore by pulping theorewith water, conditioning the pulped ore'in an acid medium at apI-I of2.5-to5'.0 with asulionatedpetroleum hydrocarbon promoter with orwithout fuel oil'and a suitablefrother, subjecting the conditioned pulpto froth. flotation, and removing the froth flotation concentrate. Sincealaskite and certain other feldspathic ores contain both micaceousmaterials and garnets, known to require, respectively, a cationic .andan anionic promoter for flotation, it might be expected-that suchprocess would be inefiective for producing ceramic-grade feldspar bysimultaneous removal of iron-bearing impurities of both types.Laboratory tests reported in Example I, below, and plant experience havetended to confirm this assumption.

A process now in use for the removal of ironbearing-impurities fromfeldspathic ores containing iron both asmicaceous materials and asgarnets requires two flotation steps for iron removal. In the firststep, the ground, screened, and deslimed ore is conditioned at about percent solids with appropriate amounts of sulfuric acid, fuel oil, acationic promoter, usually a long-chain fatty-acid amine, and a suitablefrother, usually a crude or refined pine oil. The conditioned pulp isthen diluted and subjected t frothfiotation, and

a flotation concentrate consisting mainly of micaceous impurities isremoved.

In the second step, the resulting flotation tailing is partiallydewatered in a hydraulic classifier and then conditioned at about 65 percent solids with appropriate amounts of fuel oil, sulfuric acid, ananionic promoter, which may be a sulfonated petroleum hydrocarbon, and asuitable frother. The conditioned pulp is then subjected to frothflotation, and the flotation concentrate, consisting mainly of garnetimpurities, is removed. This process has proved successful for theproduction of ceramic-grade feldspar from such ores but, since twoseparate flotation steps are required to reduce the iron content tosufficiently low value, it is necessarily complicated and requiresequipment, reagent, and handling expense exceeding that of a one-stepprocess.

The prior art, however, as typified by U. S. Patent No. 2,483,192,column 4, lines 74-75 ff., and by an article entitled F1otationchemicalsfor non-metallic minerals, Rock Products 49, Sit-93+, December 1946, hastaught that cationic and anionic flotation promoters cannot be usedtogether in a single step because they are antagonistic to each otherand require different conditions for effectiveness.

It is an object of this inventionto provide a onestep flotation processfor the removal of iron from feldspathic ores containing iron both asmicaceous materials and as garnets.

Another object is to provide a method for the production ofceramic-grade feldspar from feldspathic ores containing both micaceousmaterials and garnets.

Other objects and advantages will become apparent as this disclosureproceeds.

I have found that these objects may be attained by simultaneouslyconditioning a suitably ground and deslimed pulp of feldspathic orecontaining iron both as micaceous materials and as garnets with suitableamounts of a cationic promoter comprising a long-chain fattyacid amineand with an effective amount of an anionic promoter, namely, a materialselected from 'the group consisting of sulfonated oleic acid, sulfonatedred oil, sulfonated methyl esters of red oil, and Turkey red oil, in anacid medium, with or without suitable frothing and/or oiling agents;subjecting the conditioned pulp to froth flotation; and removing theiron-bearing minerals in froth as a flotation concentrate. Aflotation-cell tailing consisting essentially of feldspar and quartz isthen withdrawn and is conditioned with hydrofluoric acid and along-chain fatty-acid aminepreferably the same amine used in floatingthe iron-bearing mineralswith or without suitable frothing and/or oilingagents. This pulp is then subjected to froth flotation, and feldsparsulficiently free from iron to pass specifications for ceramic-gradematerial is recovered as a flotation concentrate.

- The drawing submitted herewith is a diagrammatic flowsheet of a.process embodying principles of my invention. Steps which are novel inthemselves are indicated by solid lines, and other steps which may benecessary in the process but which are, in themselves, old in the artare indicated by broken lines.

Reference to this flowsheet shows that alaskite or other feldspathic orecontaining iron both as micaceous materials and as garnets is fed into acrusher. A jaw crusher usually is used for the purpose of reducing thelumps of ore to such sizes as can be efficiently handled by a grindingmill. A suitable quantity of water is added to the crushed ore and it ispassed to a grinding mill, preferably a rod mill, where the ore isground to pass a 20-mesh screen. The ground ore is passed to a suitablemeans for removing 20mesh oversize material, preferably a 20-meshscreen, and any oversize is removed. That fraction of the ground ore ofsizes passing the 20-mesh screen is then advanced to a means forremoving slimes, preferably a hydraulic classifier, and substantiallyall minus 325-mesh material is separated from the bulk of the ore. Thesteps just described are old in the art and are preferred merely becauseof cheapness or convenience. Any equivalents therefor may be substitutedif desired, as it is merely necessary that the ore be reduced toparticles of such size as to pass a 20- mesh screen, and that minus325-mesh slimes be removed.

A pulp of the resulting ground, deslimed ore containing about 55 percent to 65 per cent solids is introduced into a conditioner. Sulfuric orother acid or acid salt yielding a free acidic radical in solution isadded in quantity sufficient to maintain the pulp in the pH range fromabout 2.0 to 3.6 and preferably in the range from about 2.0 to 3.1. Ihave found that iron removal is satisfactory up to pH 3.6 and above, butabove 3.6 excessive quantities of feldspar and quartz will be floatedwith the iron-bearing minerals. A material selected from the groupconsisting of sulfonated oleic acid, sulfonated red oil, sulfonatedmethyl esters of red oil, and Turkey red oil, is added asanionic-flotation promoter, and a long-chain fatty-acid amine or mixtureof such amines or water-soluble salts of such amines yielding the aminesin solution is also added to serve as cationic-flotation promoter.

A frothing agent such as pine oil may be required when certainsulfonated fatty acid materials are used, and is also added ifnecessary. An oiling agent such as fuel oil also may be added ifdesired.

The resulting conditioned pulp is then passed to a flotation cell and isadjusted to a concentration of about 25 per cent solids by the additionof water. The resulting pulp is subjected to froth flotation, andiron-bearing minerals of both micaceous and garnet types are removed infroth as a flotation concentrate.

The amount of each class of promoter required to be added in theconditioning step described above will depend on a number of factors,but mainly on the amount of iron-bearing minerals to be removed from theore and on the degree of purity of reagents employed. In general, about0.5 to 2.0 pounds of sulfonated fatty acid, acids, or fatty-acid estersand about 0.1 to 0.5 pound of long-chain fatty-acid amine or amines willbe required per ton of ore treated.

As used in this specification, the term longchain sulfonated fatty acidrefers to compounds having 14 or more carbon atoms in the fatty-acidradical, and since the sulfate group often is present to some extent incommercial sulfonated fatty acids the term is not intended to excludethe presence of acids having the sulfate group present as such. The termlongchain fatty-acid amine refers to such amines having 14.- or morecarbon atoms in the fattyfonatedti longgchadnz fatty acidt'. namelm ma.-

methyllesterss. o-fqfredi 011;. andiTurkeyrredioil; are;

' not antagonistic to cationic promoters comeprising a long-chainfatty-acid amine, :bntteach exerts its full selective-e flotation effectunder identical. conditions... Thesepromoters. may, thereforebe: usedtogether in a single flotation steps Theaexpectedantagonism is notdetectame,- although other anionic promoters such as sulfonatedpetroleum oils and.many sulfonat'ed long' chain' fatty-acid materialsare: antago:-- nistic to: long-chain: fatty-acid amines:- under similarconditions: V I.

, After removal. of iron-bearing minerals, by. flotation, 'the resultingflotation tailing .is passed to a means for rem'oving water, preferably.a. hydraulic. classifien. It..isv there. concentratediito. about". 50per. cent; solids. by; removing water: and. is; passed. to. a. second.conditioner; The. pulp: is: therev conditioned" with. suitable;

amounts. off" hydrofluoric. acid', a; long-chain; fattyeacidi, amine.(preferably the: same; used. in

the iron-removal'step describedaldove), a suitable .frothing agent, andfuel oil. The resultingconditioned pulp is dilutedjiwithi water if'neces s'ary and" is then subjected to" froth. flotation. Feldsparsufficientlylowiinyiron" for use iIIillhE ceramic trad'ezisthereby-recovered in" froth as a flotation'..concentrate.

Examples. are. given below illustrating quantie ti'es.of .Treagents.andfcondi'tien-s which have .proved. eifective for. the. productionv of?ceramic-grade; feldspar from ores containing; iron both as; micaceousmaterials and as garnets; OZtlier-ex amples" illustrate; the failure: ofmethods of the prior 'artt0 produce" such results: H

The Examples I throuehVII describe laboratory-scale batchwise tests. Ineach of these examples'the following procedure wasusedin" preparingtheorefor testing? (a)? A.600'-gram sample of. crushed' 'ore. waswetground at 25 per cent solids in a rod mill for 2 to13.minutes..

(bi)' Thevgroundl. ore was passed through. a.

mesh screen, and the 20 meshrofversize-was discarded.

(c) The. minus: 20-mesh. materiaL was. deslimed by washing .threetimes-.ona .325-mesh screen.

The quantities of reagents given in all the following examples are intermssoflpounds of reagentsperton of feed to thegrinder.

Trade names are givemfors the; reagents used,

since pure compounds areseldom employed as flotationpromoters,,and..it.may -be,necessartg to vary the amounts slightly ifother approximately equivalent materials are substitutedfor. those d6:-scribedii The? materials; identified BXIJ'tI'iGfi"? tradenames,areidefinedaszfollowsz at 7.0 per cent solidsl w-ith.0.35. lb./ton.sulfuric.

(f)t Amine:- 2217iisr: a2. mixtures ofi' lona'eeliain fatty-acida-minesi prepared from tall oil.

(g) Armac T is a mixture of water-soluble acetate salts of hexadecyl,octadecyl, and octadecenyliamine prepared from tallow.

(78)1 Reagent-r 825? is a sulfonated petroleum hydrocarbon material of;the oil soluhle; water dispersibleemahogany type.

(i): Aerofi'oat 31is.- a.-frotliing 'agentwhich some prisesabout- 6? percent thiocarbani-lid dis solvedin dicresyldithio phosphoric acid;

(7') B'-.2'3is' a syntheticfrother consi'stingessentially of higheralcohols.

EXAMBLE I.

The processor-UT SE 234835192 wastestedtowzle tel-mine itseffectivenessswith':alaskite. The ore used in this test contained 0.41per cent FezOs; Thepronioterrused wasReagentBZd? Thedeslimed'; ore: was:conditioned for -6" minutes at" 70 per" centtsolidshwith: 0535 lbi/tonsulfuric: acid? 112:11'01/ ton-.R'eagent 825; 025 lbr/ton Aerofioat3.l;andj 0:50. lid/ton of. fuell'oil. The-pulp was" diluted"toflotationdensity (about 25" percent:

: solids), ,subjectedtdfrot-h flotation; and'thefroth concentrate. wasseparated:

Visual examination of the celli tailing; corrtaining feldspar-andquartz; showed pthatremoval 'offtlie" garnet impurities-was good; butthat re moval" of misaceous" material was incomplete;-

maze lz-A wt Per" Per Por Per" Feed-3 600" i Isou'concentrate 36'; .2Feldspanconeentrate: 339 I l 66.13.- Quartztail. 135' 9639" Loss 1 9O1....-.

I gloss represents .plus 20:mcsh.material, animinusl325=meslrmm en Thefeldspar concentrate produced by this process met the specifications forglass-grade feldspar.

The feldspar, however, contained numerous black particles of biotite, aswell as clear mica; and would not have been suitable for use inhigh-grade ceramic ware.

EXAIWPLE II Inanother test, reagent BL-408 was used instead' of Reagent825 with the same ore used in Example I.

The.-.deslimed.nre.was conditioned i011. (iminutes:

acid, I12 lb./to-n RD-408;and 015' lbT./ton.fuel oil. The pulp wassubjected to froth flotation, and' tlie-frotliwas-separated? Separationofigarnets was' go-odhut mica; separation w-as=ve1';, -@poorr Theceiljtailing fCOIIlJEiHBfibDJZlQ per-cent Eezfim.

The eellltailing .wastthenlconditioned with, 15* lb.Aton.. hydrofluoric.acid,., 0.5. lla/toninel oil, 0.25:. lli/t'on B -23lf"and0'll4"Ill/tonArmac Tiand subjected to froth flotation. Separation of felii spar fromquartz was poor."

7 The results of this test are tabulated below: Separation of feldsparfrom quartz in the sec- Tabze ond flotation step was incomplete, and thefeldspar concentrate contained much of the mica that had not beenremoved in the first flotation Wt. Per Per Per Per Ste cent cent centcent Wt. A1203 F6203 siol Results:

Table 4-11 Feed 600 100.0 0.41 tii e't 3i? 5%; "0'50 e SD81 (30110611 8.Quartz tail 198 33.0 0.091 89.7 31 55, LOSS 77 Wt. A1203 F9203 s10,

The feldspar concentrate produced in this eed egg 102.3 0.41 0 a testdid not meet speclflcat ions for either glass f gfi g f 240 4M mg 0.140650 grade material or ceramic-grade, because of 15 Quartz tail 245 40.80.081 35.0 high F8203 and micaceous impurities. 91 or III E LE V In thistest, my preferred procedure was followed. Deslimed pulp was conditionedfor 10 The following Table 5-A gives the results of minutes at 60 percent solids with 0.35 lb./ton sulfuric acid, 1.2 lb./ton BL-408, 0.5lb./ton fuel oil, and 0.32 1b./ton Armac T. The conditioned pulp wassubjected to froth flotation, and the iron-bearing froth was separated.Removal of both garnets and mica was very good. The cell tailingcontained 0.0278 per cent Fezos.

The cell tailing was then conditioned at 55 per cent solids with 1.5lb./ton hydrofluoric acid, 0.5 1b./ton fuel oil, 0.25 lb./ton B-23, and0.14 lb./ton Armac T, and the conditioned pulp was subjected to frothflotation.

tests which show the iron-removal efliciency of various sulfonatedfatty-acid reagents in com-.

bination with long-chain fatty-acid amines. Table 5-B gives the reagentcombinations that were used in each of the tests reported in Table 5-A.

Results tabulated under test 5-b were obtained by the use of Ahcol 385,prepared by sulfonating tall oil. These particular results were verygood but were obtainable only when the ore was of {such nature as torequire restricted amounts of anionic and cationic promoters.

Results: When larger amounts of reagent were necessary, Table it wasfound that a definite antagonism existed between such sulfonated talloil and long-chain Wt Per Per Per Per fatty-acid amines.

r. ii; E 21 6, In each of these tests conditioning of the deslimed orewas carried out at 55 per cent solids.

Feed 000 100.0 0.41 Iron concentrate- 5.8 Table 5-A eldspar concentr 35859.7 19.5 0.032 66.8 Quartz tail 13 21.7 0. 024 97.0 oss 12.8

Percent Percent Percent Percent Test N0. F6203 in F020; in of F8203 Thefeldspar concentrate met specifications feed Feed Com Tail tall removedfor ceramic-grade feldspar in all respects. Moreover, the separation offeldspar from quartz in M8 100 no no M67 8% the final flotation step washighly selective, as s-b 0. 51 13.0 ;7.5 0.063 00.4 evidenced by thehigh SiOz content (97%) of the it: 335 m0 3;; 3;; 2,;323 33;; quartztail. 5-e 0.41 100 12.8 76.0 0. 005 88.1

EXAMPLE-IV 1 Preconditioned for 3 minutes with 2.0 lb. ton NaOH rio toIn this test, the 1dent1ca1 procedure followed desliming, I p r Table5-B' Reagents-1b.]ton Test NO. F 1

H4804 Amomc promoter Cationic promoter Frother g 5-a 0.8 2.0 Turkey redoil. 0.25 Amine 22 T 0.6 pine oi1. 5b 0.6 15Ahcol 5 0.1 Armac T"... 0.3pine oil 0.5 l5Ahco1550...- 0.2Armac do 41-0.--. 0.9 10Ahco1575"0.3A1mac T 5e 0.35 RL-40 0.32A.1mac T 0.5

in Example III was used, except that 1.2 lb./ton EXAMPLE VI Table 6-Agives the results of tests in which the effect of pH on iron-removalefficiency was investigated. The alaskite ore used in these testscontained 0.43 per cent FezOa. In these tests the deslimed ore wasconditioned for 10 minutes at per cent solids with varied amounts ofsulfuric acid, 0.85 lb./ton BL-408, 0.5 lb./ton fuel oil, and 0.32lb./ton Armac T. Following conditioning, the pulp was subjected to frothflota= tion for 3 minutes at 25 per cent solids.

11 red. oil, and with an effective amount of a cationic promotercomprising a long-chain fattyacid amine; diluting the resultingconditioned pulp with water to a concentration of about 25 per centsolids; subjecting the resulting diluted pulp to froth flotation;removing resulting froth containing both micaceous materials andgarnets; removing water from the resulting flotation tailing to aconcentration of about 50 per cent solids; conditioning the resultingconcentrated tailing with effective amounts of hydrofluoric acid, along-chain fatty-acid amine, and a frothing agent; subjecting theconditioned tailing to froth flotation; and recovering ceramicgradefeldspar in froth as a flotation concentrate.

2. A process for the production of ceramicgrade feldspar from afeldspathic ore containing iron both as micaceous materials and asgarnets which comprises mixing such ore in a ground, deslimed state withwater to form a pulp containing about 55 to 65 per cent solids;simultaneously conditioning the resulting pulp with a suificient amountof a material selected from the group consisting of water-soluble acidsand acid salts yielding free acidic radicals in solution to produce a pHof about 2.0 to 3.6 in the pulp, with an efiective amount of an anionicpromoter comprising sulfonated methyl esters of red oil, and with aneffective amount of a cationic promoter comprising a long-chainfatty-acid amine; diluting the resulting conditioned pulp with water toa concentration of about 25 per .cent solids; subjecting the resultingdiluted pulp to froth flotation; removing resulting froth containingboth micaceous materials and garnets; removing water from the resultingflotation tailing to a concentration of about 50 per cent solids;conditioning the resulting concentrated tailing with effective amountsof hydrofluoric acid, a long-chain fatty-acid amine, and a frothingg'agent; subjecting the conditioned tailing to froth flotation; andrecovering ceramic-grade feldspar in froth as a flotation concentrate.

3. A process for the production of ceramicgrade feldspar from afeldspathic ore containing iron both as micaceous materials and asgarnets which comprises mixing such ore in a ground, deslimed state withwater to form a pulp containing about 55 to 65 per cent solids;simultaneously conditioning the resulting pulp with a ;sufiicient amountof a material selected from the group consisting of water-soluble acidsand acid salts yielding free acidic radicals-in solution to produce a pHof about 2.0 to 3.6 in the pulp, with an effective amount of an, anionicpromoter comprising a material selected from the group consisting ofsulfonated oleic acid, sulfonated red oil, sulfonated methyl esters ofred oil, and Turkey red oil, and with an effective amount of a cationicpromoter comprising a mixture of-hexadecyl, octadecyl, and octadecenylamines; diluting the resulting conditioned pulp with water to aconcentration of about 25 per erals from a feldspathic ore containingiron both as micaceous materials and as garnetswhich comprises pulpingsuch ore as minus 20-mesh deslimed particles with water to form a pulpcontaining about 55 to 65 per cent solids; simul taneously conditioningthe resulting pulp with a sufficient amount of a material selected fromthe group consisting of water-soluble acids and acid salts yielding freeacidic radicals in a solution to produce a pH of about 2.0 to 3.6 in thepulp} with an effective amount of an anionic promoter comprising amaterial selected from the group consisting of sulfonated oleic acid,sulfonated red oil, sulfonated methyl esters of red oil, and Turkey redoil, and with an effective amount of a cationic promoter comprising alongchain fatty-acid amine; diluting the resulting conditioned pulp withwater to a concentration of about 25 per cent solids; subjecting theresulting diluted pulp to froth flotation; and removing the resultingfroth containing both micaceous materials and garnets.

5. A process for removing iron-bearing mineral from a feldspathic orecontaining iron both as micaceous materials and as garnets whichcomprises pulping such ore as minus 20-mesh deslimed particles withwater to form a pulp containing about 55 to 65 per cent solids;simultaneously conditioning the resulting pulp with a suflicient amountof a material selected from the group consisting of water-soluble acidsand acid salts yielding free acidic radicals in a solution to produce apI-l of about 2.0 to 3.6 in the pulp, with an eifective amount of ananionic promoter comprising sulfonated oleic acid, and with an effectiveamount of a cationic promoter comprising a long-chain fatty-acid amine;diluting the resulting conditioned pulp with water to a concentration ofabout 25 per cent solids; subjecting the resulting diluted pulp to frothflotation; and removing the resulting froth containing both micaceousmaterials and garnets.

6. A process for removing iron-bearing minerals from a feldspathic orecontaining iron both as micaceous materials and'as garnets whichcomprises pulping such ore as minus 20-mesh deslimed particles withwater to form a pulp containing about 55 to 65 per cent solids;simultaneously conditioning the resulting pulp with a suflicient amountof a material selected from the group consisting of water-soluble acidsand acid saltsyielding free acidic radicals in a solution to produce apH of about 2.0 to 3.6 in the pulp, with an eifective amount of ananionic promoter comprising sulfonated red oil, and with an effectiveamount of a cationic promoter comprising a long-chain fatty-acid amine;diluting the resulting conditioned pulp with water to a concentration ofabout 25 per cent solids; subjecting the resulting diluted pulp to frothflotation; and removing the resulting froth containing both micaceousmaterials and garnets.

7. A process for removing iron-bearing minerals from a feldspathic orecontaining iron both as micaceous materials and as garnets whichcomprises pulping such ores as minus 20-mesh deslimed particles withwater to form a pulp containing about 55 to 65 per cent solids;simultaneously conditioning the resulting pulp with a sufficient amountof a material selected from the group consisting of water-soluble acidsand acid salts yielding free acidic radicals in a solution to produce apH of about 2.0 to 3.6 in the pulp, with an effective amount of ananionic promoter comprising sulfonated methylesters of red oil, and withan effective amount of a cationic promoter comprising a long-chainfattyacid amine; diluting the resulting conditioned pulp with water to aconcentration of about 25 per cent solids; subjecting the resultingdiluted pulp to froth flotation; and removing the resulting frothcontaining both micaceous materials and garnets.

8. A process for removing iron-bearing minerals from a feldspathic orecontaining iron both as micaceous materials and as garnets whichcomprises pulping such ore as minus ZO-mesh deslimed particles withwater to form a pulp containing about 55 to 65 per cent solids;simultaneously conditioning the resulting pulp with a sufficient amountof a material selected from the group consisting of water-soluble acidsand acid salts yielding free acidic radicals in a solution to produce apH of about 2.0 to 3.6 in the pulp, with an effective amount of ananionic promoter comprising a material selected from the groupconsisting of sulfonated oleic acid, sulfonated red oil, sulfonatedmethyl esters of red oil, and Turkey red oil, and with an effectiveamount of a cationic promoter comprising a mixture of hexadecyl,octadecyl, and octadecenyl amines; diluting the resulting conditionedpulp with water to a concentration of about 25 per cent solids;subjecting the resulting diluted pulp to froth flotation; and removingthe resulting froth containing both micaceous materials and garnets.

9. A process for the production of ceramicgrade feldspar from afeldspathic ore containing iron both as micaceous materials and asgarnets which comprises mixing such ore in a ground, deslimed state withwater to form a pulp containing about 55 to 65 per cent solids;simultaneously conditioning the resulting pulp with a sufficient amountof a material selected from the group consisting of water-soluble acidsand acid salts yielding free acidic radicals in solution to produce a pHof about 2.0 to 3.1 in the pulp, with an effective amount of an anionicpromoter comprising a material selected from the group consisting ofsulfonated oleic acid, sulfonated red oil, sulfonated methyl esters ofred oil, and Turkey red oil, and with an effective amount of a cationicpromoter comprising a long-chain fatty-acid amine; diluting theresulting conditioned pulp with water to a concentration of about 25 percent solids; subjecting the resulting diluted pulp to froth flotation;removing resulting froth containing both micaceous materials andgarnets; removing water from the resulting flotation tailing to aconcentration of about per cent solids; conditioning the resultingconcentrated tailing with effective amounts of hydrofluoric acid, along-chain fattyacid amine, and a frothing agent; subjecting theconditioned tailing to froth flotation; and recovering ceramic-gradefeldspar in froth as a flotation concentrate.

MASON K. BANKS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,132,902 Lenher Oct. 11, 19382,297,689 OMeara Oct. 6, 1942 2,395,475 Gibbs et a1 Feb. 26, 19462,433,192 Gieseke Sept. 27, 1949 2,578,790 Duke Dec. 18, 1951 FOREIGNPATENTS Number Country Date 105,712 Great Britain Nov. 17, 1938 OTHERREFERENCES Bulletin of American Ceramic Society, vol. 18, No. 8, August1939, pages 286-292.

1. A PROCESS FOR THE PRODUCTION OF CERAMICGRADE FELDSPAR FROM AFELDSPATHIC ORE CONTAINING IRON BOTH AS MICACEOUS MATERIALS AND ASGARNETS WHICH COMPRISES MIXING SUCH ORE IN A GROUND, DESLIMED STATE WITHWATER TO FORM A PULP CONTAINING ABOUT 55 TO 65 PER CENT SOLIDS;SIMULTANEOUSLY CONDITIONING THE RESULTING PULP WITH A SUFFICIENT AMOUNTOF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF WATER-SOLUBLE ACIDSAND ACID SALTS YIELDING FREE ACIDIC RADICALS IN SOLUTION TO PRODUCE A PHOF ABOUT 2.0 TO 3.6 IN THE PULP, WITH AN EFFECTIVE AMOUNT OF AN ANIONICPROMOTER COMPRISING A MATERIAL SELECTED FROM THE GROUP CONSISTING OFSULFONATED OLEIC ACID, SULFONATED RED OIL, SULFONATED METHYL ESTERS OFRED OIL, AND TURKEY RED OIL, AND WITH AN EFFECTIVE AMOUNT OF A CATIONICPROMOTER COMPRISING A LONG-CHAIN FATTYACID AMINE; DILUTING THE RESULTINGCONDITIONED PULP WITH WATER TO A CONCENTRATION OF ABOUT 25 PER CENTSOLIDS; SUBJECTING THE RESULTING FROTH PULP TO FROTH FLOTATION; REMOVINGRESULTING DILUTED CONTAINING BOTH MICACEOUS MATERIALS AND GARNETS;REMOVING WATER FROM THE RESULTING FLOTATION TAILING TO A CONCENTRATIONOF ABOUT 50 PER CENT SOLIDS; CONDITIONING THE RESULTING CONCENTRATEDTAILING WITH EFFECTIVE AMOUNTS OF HYDROFLUORIC ACID, A LONG-CHAINFATTY-ACID AMINE, AND A FROTHING AGENT; SUBJECTING THE CONDITIONEDTAILING TO FROTH FLOTATION; AND RECOVERING CERAMICGRADE FELDSPAR INFROTH AS A FLOTATION CONCENTRATE.